Revert "PM / Sleep: Replace mutex_[un]lock(&pm_mutex) with [un]lock_system_sleep()"

This reverts commit 99273d27d6c5d37880fe05af44ff069bf12381ab.
Merge branch 'JBX' of https://github.com/RAZR-K-Devs/android_kernel_motorola_omap4-common into JBX